


alone together

by nilchance



Series: ain't this the life [11]
Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Dubious Consent, Kedgeup, M/M, Mating Cycles/In Heat, Overstimulation, Underfell Papyrus, a self-indulgent au of an already self-indulgent fic, cross-universe bullshit shenanigans
Language: English
Status: Completed
Published: 2018-06-29
Updated: 2018-06-29
Packaged: 2019-05-30 12:27:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 8,113
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15096701
Author URL: https://archiveofourown.org/users/nilchance/pseuds/nilchance
Summary: Sans is stuck in Underfell. Edge is stuck with Sans and in heat. It's hard to say who gets the worst end of the bargain. (A one-shot AU of the ain't this the life series.)





	alone together

**Author's Note:**

> A one-shot AU of ain't this the life where instead of starting six months after Red and Edge get stuck in Sans's universe, it's six months after Sans and Red swap universes. Of course everyone deals super well with this and everything is fine. Again, be advised that it's dubcon just because of the nature of heat fic in general.
> 
> Dubcon kedgeup requested on tumblr by reallyashamed and kamari3. Thanks for the prompt!

Papyrus was never really the door-slamming type. The worst of his teenage rebellion was pointedly doing his homework within arm’s length of Sans while glaring at him and occasionally declaring, “I’m rejecting your values, brother!” Sans lucked out.

Unfortunately, Edge is a grown monster who seems to be stuck in the surly glaring, bad fashion sense and angry door-slamming phase. He stormed through the living room too fast for Sans to get a good look at him, growled when Sans asked what the fuck, and threw the door shut hard enough to shake the house.

Sans leans against the wall beside Edge's bedroom door. There's nothing posted on the door, no ‘Papyrus allowed’ signage, just austere wood. It makes him a little sad. A lot of things about Edge do. He taps his knuckles on the door. "Knock knock."

Muffled, Edge says, "Fuck off."

"That's not how the joke goes," Sans says. "You're terrible at this."

"I'm not in the fucking mood."

"Hi, not in the fucking mood," Sans says. "I'm--"

The door swings open. Edge glares down at him, a bristling threat. Through his teeth, he says, "At least my brother had the sense to give me some fucking space."

Sans doubts that, since Edge looks outright resigned to his bullshit. "You're the one who said never to leave the house. Are you hurt?"

It wouldn't be the first time Edge has limped home burnt or bitten or with a spear jutting out from between two of his ribs. There's not much Sans can do to help, since he certainly can't heal the guy, but history says he can nag Edge into at least wrapping the wound.

"Give me some credit," Edge says dismissively. He's leaning hard against the doorframe. As Sans watches, a drop of sweat runs down one side of his face. "And spare me the overprotective brother routine. I'm fine."

Overprotective. Isn't that hilarious. Especially coming from Edge. Sans scratches at his new fashion accessory with a middle finger. "Sorry if I'm a little worried that the guy who says he's keeping me alive looks like he couldn't fight a kitten."

Edge snarls at him. "I could still kick your ass."

"You and pretty much everybody else," Sans says. "Congrats. You must be so proud. You want me to call Unundyne?"

"For fuck's sake, don't call her that," Edge says. "You're the interloper, you're the one who should have the nickname."

Sans shrugs. "Call me whatever you want."

"You won't answer to it," Edge says. When Sans shrugs again, Edge sighs heavily and turns away. It probably means something that Edge is willing to give Sans his back as he staggers over to his bed and sits down hard. "Come in, since doors apparently mean nothing to you."

That shouldn't be surprising, considering Sans's flexible relationship with time and space. Sans comes into the room, pausing when a heavy, unfamiliar scent hits him. "You sick?"

Edge gives a particularly humorless laugh. "In a manner of speaking. I'm in heat."

Sans stares at him.

He's heard of heats before, though not since that mandatory health class in college. It's a response to severe conditions like famine or war, biology’s way to keep their population up. Neither Sans or Papyrus have gone through it, although it might have kicked in after another several years in the underground with people falling down or mostly wiped out by a human kid with a knife. It makes horrible sense that heats happen here, where there are less than half the monsters that lived in Sans's universe.

"Okay," Sans says slowly. "What do you need? A doctor or something? I can call Al--"

"I need my brother," Edge says. He probably intends to sound angry, but there's desperation underneath it.

Sans doesn't wince, though it's close. He knows Edge misses his brother like Sans misses Papyrus, like they're both staggering around with half their souls gone. "Will it pass if you don't--" Sans makes a circle with his fingers and pokes a finger through repeatedly. He’s a bastion of maturity and good taste. "Y'know."

"It'll pass," Edge says. "Eventually."

"How eventually?" Sans asks.

"A week," Edge says. His jaw tightens. "My brother did it once when I was a child. It's... unpleasant but survivable."

Unpleasant. The fact that Edge is admitting that says a lot about exactly how 'unpleasant' it'll be. "And it'd pass how fast if you banged somebody?"

"A few hours," Edge says tersely. "Not that it's relevant."

Sans watches him for a moment, trying to gauge his temper. As bad as ever, probably. Fuck it, if Edge was going to kill him he'd have done it already. "Your bro seems like a pragmatic guy. Figure he'd get over it if you got it out of your system with somebody else."

Edge's fingers curl into fists. "You underestimate how badly people want me dead. I can't trust anyone with him gone."

"I haven't killed you in your sleep yet.”

Edge looks at him. His eyelights seem brighter, feverish. Poisonously sweet, he says, "Why, are you offering to help?"

They’ve had that discussion. Edge already knows his answer, so Sans saves them both time and skips that part of the conversation entirely. "So you're just gonna butch it out, huh."

Edge looks away. "I told Undyne what's going on. She'll cover my rounds. Go to her house and she'll look after you until the heat's passed."

Not for the first time, Sans reminds himself that Edge doesn't even realize he's being insulting. Never mind that Edge doesn't care whether or not Sans is insulted so long as Sans is alive to be irritated about it.

Sans shoves his hands in the pockets of his hoodie, toying with his lighter. It's a touchstone, something from home, something to prove that home ever even existed. "Yeah, no. That doesn't work for me."

"I don't remember asking for your opinion."

"What're you gonna do, sit alone in the house for a week and hope real hard that nobody shows up?" Sans asks. "I assume going into heat is a regular thing around here. What're those people who are so het up to kill you gonna think if you don't show up to work for a few days?"

Even the chaos of the first few days that Sans showed up here, when Edge had been tearing apart the whole underground to find his brother, he'd only missed one shift. Any idiot could guess he’s laid up and vulnerable.

With strained patience, Edge says, "Do you have a better plan?"

"Yeah. You stay up here with the door closed and I hang out in the living room to watch the door." They’ve been crammed in the same house for months, stuck in each other’s back pockets. Edge knows how little and how lightly Sans sleeps. It’s a point of contention. "If anybody tries to get in, I'll shortcut into your room, grab you, and we both get the fuck out."

"That's unacceptable," Edge says.

"So's the plan where I leave you here to get killed, buddy," Sans says. Frisk has come and gone here, didn’t make it past this Undyne, and didn’t come back. There are no resets, no second chances. What's dead stays dead. It forces him into the awkward position of having to care. "I really don't want me to show up and kick my ass. That's a little too much psychodrama for me."

"You're going to Undyne's," Edge says, a warning in his voice. The menace is kinda undercut by the fact that he's hunched in on himself, shaky and sweating.

"Let's say you can drag me all the way to Waterfall right now," Sans says. He lets his tone imply how sincerely he doubts it. "There's exactly jack and shit you can do to keep me from taking a shortcut right back here whenever I want. How about we save us both some effort, huh?"

Edge drags a tired hand over his face. "If you'd ever met my brother, you'd realize how impressive it is when I say you're just as big a pain in my ass."

If Sans ever meets Edge's brother, he's going to punch the guy in the fucking face. And then get killed for it, naturally, but it'll be a very satisfying few seconds. "Dunno what you expected," Sans says. "You want an ice pack for your junk or something?"

"I want you to go to Undyne's where it's safe," Edge says. "I'll settle for you just getting out of my face."

"Not a big fan of my bedside manner, huh?" Sans asks. Edge growls wordlessly at him. "Fine. I'll be downstairs. Yell if you need anything."

"Your absence will do," Edge says irritably. He starts stripping off his jacket and gloves. A moment later, his shirt follows.

Averting his eyes from all the scarred white bone being revealed, Sans heads for the door. When he's almost escaped, Edge calls after him, "Put furniture in front of the door. Something heavy."

"I figured," Sans says. Might slow them down and give he and Edge a couple minutes to bail. It should probably worry him that he’s starting to think like he’s from here, but he’s always been a survivor for better or worse. Usually worse.

"Not just the front door," Edge says. There's a strange tension in his voice. When Sans looks back at him, Edge keeps staring fixedly at the floor. "The door to my room."

"You going through heat or turning into a werewolf?" Sans asks. Edge doesn't respond. Sans exhales through his teeth. "Yeah, all right. If you want."

Edge is a killer. A pushy, condescending murderer who fucks his own brother. He spent the first few hours Sans was in this universe interrogating him at weapon-point, demanding to know where the hell Sans put his brother. He is, in short, kind of a dick. But he wouldn't hurt Sans because he knows one hit would kill him. He especially wouldn't force himself on Sans. Sans can trust that much, at least, even if Edge apparently doesn’t.

He shuts the door to Edge's room and finds a bookshelf to teleport in front of the door. He gives it a little shove so it scrapes across the carpet, making noise so Edge knows Sans did what he asked. Maybe it’ll give him a little piece of mind. Then he goes downstairs and plants himself in front of the couch. Doomfanger, curled up in a ball on Edge's side of the couch, slits open his good eye and gives a warning hiss.

"Same to you," Sans says. Absently, his fingers find the collar. He hooks a thumb under it, pulling it away from his neck. The fucked up thing is that it doesn't feel like it's constricting his breathing anymore. He's getting used to it.

Somebody else's collar. Somebody else's life. Another Sans who lingers like a ghost in the house.

"Hey, asshole," Sans says, because if he's talking to himself, he might as well actually be talking to himself. "You'd better be treating my bro right."

He can have faith in Edge’s basically good intentions. He’s never been able to trust himself.

His only answer is silence.

***

Sans drops the wrench in his hand and leans back against the couch, glaring at the machine he brought into the living room. He can’t concentrate on simple maintenance. He can’t hear himself think over the utter silence coming from Edge’s room.

Three days. Three long, sleepless days. He’s been trapped in this house for six months, aside from jaunts to the shed and to this Undyne’s, but the walls have never felt closer. Nobody’s come sniffing around. He can’t even watch TV, considering that Asgore is letting Mettaton handle some of the public executions. There are too goddamn few monsters left already and Asgore is killing his own people.

The one good thing about this whole switching universes thing is that it was Sans who ended up here, not Papyrus. Or hell, maybe Papyrus would be out there changing things for the better by sheer stubbornness and his talent at kicking ass and dropping guilt trips. All Sans is good at is keeping his head down and enduring in the bitter hope that it’ll all be over soon, one way or the other.

It’d be over faster if he could figure out the machine. This Sans made some impressive progress, seeing things Sans himself didn’t, missing things Sans saw clear as day. His solution to the problem with the entropy engine was frustratingly elegant. But in the end, the guy was just as stuck as Sans was. So Sans spends his days banging his head against the cold bulk of the machine because there’s nothing else he can do.

It’s useless to try to concentrate, not when he’s busy listening for any signs of life from upstairs. He’s not gonna be able to think unless he’s sure Edge is okay.

He gets up and climbs the stairs to Edge’s room. Listening at the door isn’t any more informative. He hesitates, then raps his knuckles on the bookshelf. “Edgelord?”

He gets more silence for his trouble. Adrenaline makes the back of his neck prickle.

(What if he’s been alone in this house for the last three days? What if all there is behind the door is an empty bed and a dusty carpet?)

“I’m coming in,” he says, trying for a light tone. “Hope you’re decent.”

Nothing. Not even a protest. If he wasn’t already decided, that would do it. 

A second later, he’s in the close, humid darkness of Edge’s room. The scent of sweat and spent magic hits him like a hand covering his mouth and nose. He can taste it.

Edge is still on the bed, curled up into the fetal position. He’s cuffed one of his wrists to the bed. He’s breathing evenly and deliberately, like he can control the pain if he controls himself. And he is in pain; Sans can see it written in every angle of his body. Edge has skittish reflexes and more than once Sans has gotten a weapon in his face for appearing too suddenly behind him, but Edge doesn’t jerk into a defensive position or create an attack. He’s holding himself very, very still.

Sans doesn’t want to see Edge like this. Edge sure doesn’t want to be seen when he’s this vulnerable, made up as he is of 95% stubborn pride. It’s too tempting for Sans to just leave the way he came so he doesn’t have to look at this anymore. It’s making his soul throb in useless sympathetic pain.

“Unpleasant?” Sans asks.

“Get out,” Edge says through his teeth.

“Looks a little worse than unpleasant,” Sans says. He checks Edge, ignoring the snarl it earns him. Call it revenge for the many, many times Edge has checked him as soon as he gets home, like noodling with the machine all day is going to kill him. 

80 HP. Way too low, considering that Edge maxes out at 750. Sans takes an involuntary step forward and brakes hard at the noise Edge makes, all want and agony. Instead he stands there, hands open and empty. He can’t heal. He doesn’t know what would happen if he dragged Undyne here to help stabilize him, whether Edge would attack her for being in his territory. He can’t bring Edge’s brother back to fix this.

Panic won’t help anything, though looking at Edge’s stats is making it rise up in his chest to choke him. Sans tries to sound calm. “Your HP’s low. Can you keep food down?”

“I have this under control,” Edge says. He’s shaking hard enough that it’s making the cuff rattle. “I’m fine. Leave.”

“You’re not fine,” Sans says.

“You smell like him,” Edge says. His voice is scraped raw. Unsteady. It pulls at Sans’s soul like a fish hook. “So get out before I hurt you, you stupid asshole.”

Edge doesn’t look like Papyrus. Too many scars, too sharp teeth, all the lines of his face rewritten by 20 years of resting bitch face. But it still hurts to hear that little break in his voice. All of Sans still screams at him to fix it.

He knows exactly how he could fix this.

Hasn’t he fucked people for stupider reasons? Does sex mean anything to him anymore? He could do it with his eyes closed. Easy. All he has to do is--

He leaves the room. Downstairs, where it’s safe, he sits on the sofa and puts his face in his hands.

He can still smell Edge on his bones.

***

Sans’s resolve lasts a whole twenty minutes.

When he drops into the bedroom, something has changed. The air is still thick with the scent of heat and the unsteady rasp of Edge’s breathing, but Edge doesn’t immediately start snarling at him to get out. It’s like he knows, like he can smell it on him. He watches Sans, still and predatory. There isn’t much rationality behind that look.

"What are you doing?" Edge says.

"Something stupid, probably," Sans says. He unzips his hoodie and shrugs it off.

“You shouldn’t be here.”

Doesn't that just sum up the whole situation. Sans shouldn't be here. He shouldn't be in this universe. He definitely shouldn't be in this bedroom. He shouldn't be kicking off his slippers and moving closer.

"I'm throwing you a bone, buddy," Sans says. Edge draws in a breath, his eyelights briefly guttering out. "Tell me no and I’ll get out."

Edge lets out a shuddery, humorless chuckle. "You don't want this."

"I don't see a better option," Sans says. He skims out of his shorts, and Edge's eyelights go sharp and hard. He swallows. "I wanna help you. Let me."

"Don't be such a fucking martyr." Edge is holding on by his fingertips, trembling. "I can’t--"

"Nah," Sans says. He strolls casually into Edge's space. "So does this just involve some fluid exchange or--"

It's no surprise when Edge grabs him by the front of his shirt and hauls him onto the bed. He has no idea what to expect from there, but it's not for Edge to pull him down and kiss him, his free hand cradling the back of Sans's neck. Sans can feel the leashed violence in it, but Edge licks at his teeth, asking permission instead of just shoving inside. Sans opens his mouth and Edge’s tongue slips past his teeth, tasting him. Edge moans shakily, relief and deep hunger, radiating heat like a furnace. Despite the whole situation, Sans wants to curl up against him and shake off some of the persistent chill.

"It's okay, dude," Sans says when they have to come up for air. "Just do what you gotta."

Edge growls at him, the _you're being stupid_ growl. Edge has a variety of growls for every occasion. He pulls Sans even closer. His hand settles on the hem of the t-shirt, and Sans pulls back to say, "That stays on."

It's not as firm a statement as he'd like. His head is spinning from the warmth and the scent of Edge's bones, like the heat is contagious. If somebody breaks into the house and attacks, his reflexes won't be as fast as they usually are.

Welp. Too late now. He's relatively sure, 75% sure, that if he told Edge to stop, Edge could do it. But he's already damned himself. He's already gonna have to live with knowing what Edge feels like pressed against him in the dark, what Edge’s mouth tastes like.

To his credit, Edge lets go of the shirt. His fingers slip under it, curling around that spot in the middle of Sans’s spine. Edge has the cheat codes from years of fucking his version of Sans. Sans swallows a little noise and reaches for the cuff.

Fast as a striking snake, Edge catches his wrist. Sans freezes, and Edge gives him a kiss that's almost gentle. "Leave it."

"Dude," Sans says. He's breathing a little unsteadily. "Your shoulder's gonna pop out of socket if we try to--"

"I want you to be able to run," Edge says.

Sans laughs. He can feel himself sliding into that easy role, the one-time fuck who knows how to be what someone wants. It's safer ground. It isn't really him here, doing this. It's someone else.

He leans close and bites Edge's jaw. "Do I look like I'm running?"

"No," Edge says. There's a dark satisfaction in that one word that makes Sans suppress a shiver. He releases his grip, and Sans resists the urge to rub his wrist. "You don't."

Sans braces himself, then reaches between them to rub Edge's cock through his pants. Edge shudders but holds still while Sans feels him out, tracing the shape of him. Edge is big. Very big.

"Lemme suck you off," Sans says. His voice comes out surprisingly steady. Good for him. "It'll help."

That's not gonna be enough to burn it out of his system, not by itself, but Sans is trying not to think about that part.

Edge’s hand settles on the back of Sans's neck, a reassuring weight. Instead of answering, he rolls onto his back and lets his knees fall open, making room for Sans between them.

Sans has done this before, dozens of times. It's almost easy to make himself comfortable between Edge's legs. The sound of his zipper coming down is very loud. Edge's magic is red as marrow, shocking against white bone and black leather. Sans hesitates, then reaches into Edge's fly and wraps his fingers around his cock. Edge hisses, his hips jerking once before he locks himself into trembling stillness. Sans wonders how long his magic's been formed without relief.

Sans frees Edge's dick. It manages to look even bigger than it felt. He bends his head and takes an experimental lick, dragging his tongue up the upside, lapping up a bead of precome.

Edge's grip tightens hard on the back of his neck, but he doesn't force Sans's head forward. If Sans pushes him much harder, Edge is going to snap. Sans grasps the base of Edge's dick a little more firmly and licks at the head, taking what he can of it in his mouth. There's a brief, sharp snap of chains as Edge reflexively moves to grab at him and comes up short.

The taste of Edge's magic is strong and surprisingly sweet. Sans can feel precome sliding down his throat. He doesn't screw around. He gives Edge everything he's picked up from years of practice on his knees. Edge holds onto him like Sans is keeping him anchored, or maybe like Edge is keeping Sans anchored, the two of them clinging to each other in the dark.

Edge is quiet, just shuddering breaths and the occasional filthy groan. It startles Sans when he breaks the charged silence with a sudden, startlingly coherent, "Don't stop."

Sans wasn't planning on it, but he gives Edge's thigh a quick squeeze to show that he heard. Edge strokes the back of his neck, fingering his collar, absent fondness meant for someone else. It's the first affectionate touch Sans has had in months and his gratitude, his hunger for it, chokes him. He speeds up out of spite.

"Fuck," Edge says, curling his hand around the curve of Sans's skull. "Yes. Let me come in your mouth."

Stupidly, Sans can feel himself blush at the bluntness of it. He gives Edge's leg another squeeze, hoping he realizes that it's a _yes_.

Maybe Edge does realize and maybe he doesn't. He finally holds Sans's head down, thrusting twice into his mouth, making Sans open his mouth until his jaw aches so that Edge doesn't scrape himself raw on his teeth. Then Edge comes, sudden and sharp and silent.

There's a lot of jizz to swallow, like it's three days' worth all at once. It burns going down like taking a shot of cheap alcohol. Sans manages to get most of it, though he can feel some trickle past his teeth and down his chin. He pulls off Edge's dick, panting and dizzy.

Which is when Edge drags him up by the back of his neck like a misbehaving puppy, leaving him awkwardly straddling Edge's pelvis. Sans starts to protest and loses the words in Edge's mouth as Edge kisses him again, claiming Sans's mouth as his territory.

When Edge lets him up for air, Sans manages, "Holy shit, warn a guy."

Edge drags his thumb over Sans's chin, capturing the little bit Sans missed. "You swallowed."

"Yeah," Sans says, half a question. "Sure did."

"Good." Edge sounds so richly approving. Sans hopes like hell his shudder just seems like he’s trying to catch his breath. “That’ll make things easier.”

Oh fuck, it _is_ contagious. It makes sense from a biology standpoint, that an exchange of magic drags the fuckbuddy down with them. Increases the chances for a successful mating if everybody’s nice and receptive. Maybe if Sans keeps it clinical, he won’t bolt from the room.

Edge brushes his thumb against Sans's teeth, and Sans gets the jist. He licks clean the little bit of come he missed and Edge nearly purrs.

When Sans shifts his weight a little, he can feel Edge's cock press against him. It's hard like Edge didn't get off at all. Sans rocks against it, making Edge shudder again. It's not the biggest dick he's ever put in his mouth, but it's definitely bigger than the biggest thing he's had in his pussy. He doesn't usually let people fuck him. If he tries to take it without any warm up, he’s going to hurt himself and die very, very stupidly. It's making it a little difficult to form his magic, his soul clenched like a fist despite the faint, promising warmth of arousal gathering at the base of his spine.

(How is he supposed to look Papyrus in the eye when he gets home?)

(Ha. Like he's ever getting home.)

"You got lube, boy scout?" Sans asks, trying to grin easily. It seems like getting off cleared Edge’s head a little and they have a moment. He keeps gently grinding on Edge, friction against the underside of his pelvis. He just needs enough to get his magic to form something Edge can fuck. It'll be easy to hold the magic there once it's formed. He can let himself go numb then.

If he has the choice, that is.

Edge searches his face, eyes narrowed, then demands, "Kiss me."

Despite himself, Sans snorts. "It's cute that you're bossing me around when you're the guy handcuffed to the headboard." Then he leans down and kisses him anyway, undercutting some of his point.

Edge makes a deep, hungry noise into his mouth, licking at his teeth until Sans opens his mouth. When Sans does, Edge slips his hand beneath Sans's shirt again, gripping his spine in that same spot, rubbing his thumb against the cartilage. His grip is tighter than Sans would usually let anyone get away with, but the pressure sends heat radiating down Sans's body. He shivers, relaxing under the touch, and grinds against Edge again.

"Your bones are so smooth," Edge murmurs into his mouth. "No scars."

Sans thinks of the slightly crooked finger on his right hand, the one that didn't heal right. He thinks of his soul. "Just lucky, I guess."

"I'd like to see them," Edge says.

Sans shakes his head. "One night only, buddy.”

"How kind of you," Edge says. There's a tinge of acid beneath the words, but his hands are gentle as he lets go of Sans's spine and runs his fingers up each vertebra towards his ribs. "No scars? Not even here?"

He traces the hot, sensitive line of the scar that doesn't bisect Sans's sternum. Sans swallows a moan, stiffening against him, bracing for Edge to hurt him, but the touch is light. He wonders how much Edge knows about where that scar came from. He doesn’t want to know the answer. Half-laughing, Sans says, "Cheater."

"I learned from the best," Edge says, almost wistful. 

He pets the not-scar again, again, barely making contact, and Sans burns. When Edge takes his mouth again, it's harder to keep quiet. Every stifled noise makes Edge kiss him more hungrily, demanding more. Sans lets himself grind against Edge, a release valve for everything that he's feeling. When his magic finally settles into place, the relief drags a moan out of him.

Okay. Thank fuck that part's over. Sans sits up, ignoring Edge's dissatisfied expression, and starts to reach between his legs to finger himself open. He's off his game, moving slower than usual, because Edge grabs him by the wrist before he can get where he’s going. Edge is the grabby type, apparently. Sans isn’t exactly surprised.

“I’ve got this,” Sans says, trying to sound reassuring and only managing to sound impatient. “It won’t take long, I swear, I just need a second.”

Edge looks at him, his expression tight. He gentles his grip on Sans’s wrist. "I know I forced you into this, Sans--"

"No," Sans says immediately, because like hell he's letting Edge go through this thinking he's raping him. "No, you didn't, you were gonna just suffer through it, I chose this--"

"At least let me make it good for you," Edge says.

It's too honest. For all the orders Edge has snapped at him, the ones Sans has obeyed and the ones he's ignored, this is different. This is a request.

It's a whole different thing, gritting his teeth and enduring this versus letting himself enjoy it. That seems like one step off a cliff and a long, long drop.

Sans is already going to hate himself after this. There's no reason Edge has to hate himself too.

Sans averts his eyes towards the door like he's actually listening for intruders instead of the hammering of his own pulse. He swallows. "Okay. If you want.”

Edge’s thumb strokes the inside of Sans’s wrist, more like he’s trying to be reassuring than arousing. “I want you to sit on my face.”

The blush scalds across his face. “Don’t just say it like that.”

Edge raises a brow, looking more like himself than he has since this started. “Would you rather I say please?”

Fuck Sans’s entire life. He climbs off Edge and awkwardly knee-walks up the bed. It’s hard to keep his nerve when Edge is watching him like that, like he’s mistaking Sans for his brother or like this means anything besides awkward conversations in the morning. He manages. He doesn’t even knee Edge in the head when he straddles his face. He’s so distracted trying not to balk that the first hot, gentle drag of Edge’s tongue up his slit catches him off guard. He actually yelps, a humiliating little noise, grabbing onto the headboard with a death grip. 

Edge chuckles because he’s an asshole, his free hand settling on Sans’s thigh like he’s gentling a horse. Or maybe not, Sans doesn’t know jack shit about horses. He doesn’t know about anything. He doesn’t know how he got here, clinging to the headboard as Edge’s tongue finds his clit. 

Six years worth of dry spell. It took a little time for his body to remember how this goes but oh, it’s warming up now. His body doesn’t care that this is fucked up. It only cares that Edge’s mouth is lush with heat, moving slow like they have all the time in the world, coaxing wetness from Sans’s cunt and making his clit swell under each lick.

Sans presses his forehead to the headboard, eyes squeezed shut, panting. He concentrates on breathing, on trying to be quiet, but when Edge finally slips one long finger inside him, he can’t choke back a low moan. It’s too good. His soul feels tight and hot in his chest, sweat trickling down his spine and soaking his shirt to his ribs. He’s shaking and it only gets worse when Edge adds another finger. If Edge would just give him a minute, one goddamn minute to clear his head...

He’s been eaten out before. He’s had fingers inside him. He’s got control issues but he at least gave it a try a couple times to keep people happy and to see what the fuss was about. People have gotten him off before. But nobody’s taken him apart like this, with such patient deliberation, like they see him down to his marrow and still think he deserves to be treated well. It’s bullshit. It’s absolute bullshit and he’s going to get off on it anyway if Edge keeps going. He can feel the pleasure building, his cunt twitching little warnings around Edge’s fingers.

Maybe he could fake an orgasm? No, it’s gonna take more stretching than this to prep for Edge’s dick. Three fingers, maybe four. Even if Sans pretends to come, Edge isn’t going to stop. It’ll be easier for them both if Sans just lets it happen. 

(Such a convenient excuse.)

The heat is blossoming like a slow detonation, making his pulse beat harder and his breathing come faster. He’s relaxing whether he wants to or not, dizzy with it. He can feel himself softening and opening under Edge’s touch. When Edge switches from spreading his fingers wide to curling them in, beckoning, Sans makes a noise that’s as good as begging.

Edge growls against him, curling his fingers again, rubbing slow and steady only to release and then do it again. The building pressure unlocks Sans’s throat and he whispers a shaky, “Oh fuck.”

Edge’s bound hand flexes in his cuff like he thinks he isn’t touching Sans enough already. His tongue toys with Sans’s clit, teasing the hood back. Sans curses at the more direct touch, pressing involuntarily into Edge’s mouth. There’s a warning prickle of teeth that only makes him hotter before Edge readjusts and it’s just soft, wet tongue again. Sans is shaking so hard he can hear his bones rattling.

“Don’t--” he blurts, and it’s half _don’t make me do this_ and half _don’t ever stop_. Edge pauses, and Sans takes that final, fatal step off the ledge. “More.”

Edge slips another finger into him, easy as parting water, and it’s enough. Sans is already coming hard, wracked with it like guilt, before Edge gives him anything else. But Edge is a generous ( _lover_ ) emergency fuckbuddy, damn him, and he doesn’t stop, stroking Sans inside, licking up the flood of wet magic Sans can feel slipping from him. 

When Sans is jerking against him with every lick, too fucked up to pull away, Edge finally eases off his clit. Sans gasps, a watery little noise, as Edge adds a fourth finger. It should burn, Edge’s hands aren’t small, but there’s no resistance. Sans takes Edge’s fingers like this is what he was meant for. His body is throbbing for more than fingers. There’s a gnawing, desperate hunger in him. He shudders, grip tightening on the headboard until it creaks, as Edge curls his fingers in again, rubbing that same place inside him, coaxing. Then Sans hits the quick release on the cuff around Edge’s wrist.

Things happen fast after that.

Edge pulls his fingers out and Sans whines at the sudden loss. Then Edge moves him like it’s nothing, putting Sans on his back on the bed and pinning him there with Edge on top of him, Edge’s mouth on his. Sans can taste himself in Edge’s tongue. Head swimming, Sans goes to grab onto him. Edge pins his arm to the bed beside their heads. It doesn’t hurt but the meaning is unmistakable. Edge’s fingers are slick against his ulna from being inside Sans.

“Why must you always push me?” Edge says against his mouth.

“Maybe I want you to do all the work,” Sans says. He manages to sound surprisingly casual.

Edge chuckles, a rough drag of sound that Sans feels in his pelvis. “Lazy bastard.”

“Yeah,” Sans agrees. He grinds up into Edge, not even sure himself if he’s trying to move things along or just fix the emptiness inside him. The smell of Edge’s bones fills his head until it feels like it’ll come spilling out of his eyesockets. He shivers, testing Edge’s grip, which tightens just a little in warning. It doesn’t hurt. Edge knows what he’s doing, fucking somebody with low HP. He’s not a huge fan of the idea that he won’t be able to really touch Edge back, earn his keep, but knowing Edge has him is unexpectedly comforting, which he’s not going to examine now or ever. “Let’s get this show on the road, huh? Cum on.”

“Impatient? You--” Edge stops, then says in an entirely different tone, “That’s not even a creative pun.”

“I’m not exactly firing on all cylinders here, buddy,” Sans says. It’s getting harder to think as the seconds tick on. He has no idea how Edge is managing complete sentences. Practice being in heat, maybe. He shifts under Edge again, restless. “Quit playing with your food and show me what you’ve got.”

Maybe he shouldn’t bait someone who has him so utterly trapped, but… Edge won’t hurt him. Even now, Edge has all of Papyrus’s control. (Don’t think about Papyrus.) He won’t hurt Sans unless he chooses to.

Edge kisses him again, long and thorough, until Sans is squirming under him to try to hurry things along. When they part, Edge murmurs, “If you need me to stop, tell me. If I don’t stop, don’t hesitate to use force.”

“Kinky,” Sans deadpans.

“I’ve seen you fight,” Edge says, which is rude. They agreed to never talk about that. By which Sans means he told Edge to stop asking goddamn questions and Edge didn’t tell him to fuck off, which was practically a signed guarantee as far as Sans is concerned. “You can handle yourself. That’s the only reason I didn’t throw your ass out the second the cuffs came off.”

Look at Edge, talking about conditions like either of them are going to walk away. Sans can’t exactly feel his fingers and he’s burning up. He can’t even remember being cold. But this’ll move along faster if he just agrees, so he says, “Yeah, okay. I’ll tell you to stop.”

Another searching kiss. Edge breaks it to ask, “Comfortable?”

Sans facepalms. “Aside from the part where I’m gonna die of old age and you’re gonna die of blue balls, this is great.”

“And here I thought your trait was patience,” Edge says, but the snark doesn’t have his usual bite. Edge shifts, aligning their pelvises. With the height difference, it leaves him looming above Sans. Sans’s pulse picks up at the promise of getting fucked and he winds his legs around Edge’s narrow hips, pressing his free hand to the back of Edge’s ribcage. Edge takes his dick in hand, his weight pressing Sans deeper into the mattress. It should be claustrophobic but Sans feels surrounded, protected, in a way that’s going to be mortifying in retrospect. Some part of him is very satisfied with Edge holding him down like this. He’s gonna blame it on the heat.

Edge rubs himself along Sans’s slit, getting himself slick. The third and fourth slow, deliberate slides are just gratuitous, the broad head of Edge’s dick rubbing all over Sans’s clit, winding him up. Judging from the blowjob, Edge is probably leaking precome, marking Sans with streaks of red.

“Now you’re just being a dick,” Sans says unsteadily. He digs his fingers into Edge’s back. “Do it already. Or are you all talk?”

It’s transparent, the worst attempt at manipulation he’s made in years. Edge scoffs, clearly seeing through it, but lines the head of his dick up to Sans’s pussy. He starts to push in and the slow, slow pressure of it makes Sans curse, his head snapping back against the mattress. Even with the fingering, Edge feels big inside him. His body opens, letting Edge in. The moan escapes Sans like Edge is physically pushing it out of him. 

And then Edge is fully inside him. Sans clenches uselessly around his dick, tugging at Edge’s grip around his wrist just to feel that Edge is still holding him down. He’s into it to an unfortunate extent. Edge exhales, slow and shaky. When Sans looks up at him, Edge’s eyes are closed, color burning high across his cheekbones, a little tick in his jaw. He’s struggling not to move, not to take too much. 

Sans feels something then, a kind of painful tenderness, like touching a bruise. He shoves it down hard where he doesn’t have to feel it. It’s dangerous. Too soft, he says, “C’mon. I can take it.”

Edge huffs a laugh. Says, “I’ve realized that.” He pulls out until only the tip is inside Sans, spreading him open, and Sans feels his body clutch tight at Edge like it’s trying to keep him. Then Edge pushes back into him, slow and inexorable as a tidal pull. Sans bites back a moan, letting his head fall back against the bed.

Edge braces himself on one arm, giving Sans a little space to breathe. Sans tries to pull him back down but Edge stays stubbornly put. Edge thrusts in again a little more firmly with a soft, wet noise. They’re way beyond modesty now but Sans’s face burns anyway.

Frowning thoughtfully, Edge readjusts his position a little and slides into Sans at a toe-curling angle. Sans chokes on his words, shuddering, and a feral satisfaction lights Edge’s eyes. Once he finds that angle, he stays there, striking over and over that place inside Sans that hits him like a punch. Sans never really came down from the first orgasm, his whole body tight and oversensitive. The pleasure is welling back up in him and he could come like this, just from Edge toying with him.

“Edge,” he manages shakily, and it doesn’t sound like him. It doesn’t sound like somebody in control. The metronome precision of Edge’s hips falters and he pushes into Sans a little harder than he probably means to, hard enough rock the bed beneath them. Sans scrabbles at his shoulders, arching into it. “C’mon--”

Edge makes a rough noise, almost a snarl, and fucks into him hard again. Again. Again. The headboard rattles in the bedframe. Edge’s hand around his wrist is the only solid ground in the universe. Sans’s tongue is his weapon but the words have deserted him. He’s disarmed. He tries to keep quiet but when he comes again, he cries out, sharp and grateful. Edge falters, fighting the heat, struggling to stop and give him a second. Trying not to hurt him. Trying to be kind. Sans grinds viciously up into him, fucking himself on Edge’s dick, begging with his body since he can’t find words. 

Edge makes a noise that might be a laugh, incredulous and pleased. Then he pushes into Sans hard, reclaiming the same speed and pace, driving all the breath out of Sans on a long groan. The overstimulation skims close to the point of pain and then too fast back into blinding pleasure. His body aches like a fever. Edge shudders above him, leaning into him, and Sans yearns towards him like they can somehow get closer when he’s so full of Edge already.

He can feel the second that Edge’s control slips and he goes from giving to taking, but it’s nothing that Sans isn’t offering. He wants it, selfishly, greedily, for his own sake. He wants this. Edge is shaking against him, his soul dripping silver fluid in fat hot drops onto Sans’s chest and throat, marking him up. With Edge leaning into each thrust, chasing his own pleasure, making use of Sans, the base of his dick glances against Sans’s neglected clit, little jolts of friction that make Sans’s breath hitch in his throat every time.

Suddenly Edge’s spine bows beneath Sans’s hand and he shudders hard. His come is a warmth that spreads inside Sans, Edge’s slowing thrusts pushing it deeper into him. Sans shivers, his wrist twisting in Edge’s grip, his free hand kneading restlessly at Edge’s shoulder.

Edge grinds against him, slow and deliberate. He shifts his weight, reaching between their bodies. Sans tenses in anticipation, his hips jerking as much as he can with Edge so thoroughly pinning him down. When Edge’s fingers settle on his clit, rubbing little circles, it drags an unwilling whine out of Sans’s throat. He was so close when Edge came. He’s exhausted and sticky and the heat’s still on him, demanding more. Edge is still so hard inside him. Edge needs him.

“Keep goin’,” he says. He has his words back a little but the accent Gaster ordered out of him is slipping into his voice like when he’s half-asleep or drunk. “S’okay. M'fine. ‘M good.”

“Yes,” Edge says, unexpectedly soft. “Yes, you are.”

Sans comes like it’s going to kill him.

***

Sleep clings to Sans like black tar, trying to hold onto him. It would be so easy to ignore the tug of nagging anxiety, of missing something important, and sink back down. He's warm and his head is resting on something that rises and falls with rhythmic breathing, lulling him, coaxing him into just another five minutes...

His head is on Edge's shoulder. Realization strikes him, and memory follows up with a suckerpunch while he's already on the ground.

Last night. Edge. Being fucked into the mattress. A delirium of noise and sensation and cloying heat, Edge's hands and cock and tongue. He doesn't remember passing out from exhaustion or sheer overwhelming sensory input, but he must've. What he can remember, more embarrassing fever dream than reality, says that his stamina held out way longer than he thought it would.

(He'd begged for it in the end. He has a dim memory of Edge hushing him, brusque but not unkind, and sliding down until his mouth was between Sans's thighs--)

Welp. That's sure several hours Sans is going to banish to the dark corners of his memory. Yep.

Experimentally, Sans tries to move. He expects for his pelvis in particular to protest last night's shenanigans, but gets only a dull full-body ache. Thoroughly used, yes, definitely, but Edge was still being careful. Even as far gone as they both were, even if Sans would’ve given him pretty much everything, Edge had tried not to hurt him.

Sans cranes his head to look at Edge. Six months he's been here and he's never seen Edge asleep before. Sleep makes the circles under his eyes and the ugly jaggedness of the crack in his skull more stark even as it softens the severity of his frown. It makes him look his age. Too young for the LV he has. Too young to be so scarred up and harsh.

He doesn't look like Papyrus at all.

Sans checks him. His HP is at 120; as Sans watches, it climbs to 122. Edge's body is recovering on its own without the heat draining him. Or hell, maybe Sans's pussy has nutritional value. A medical miracle.

Edge needs sleep more than food; Sans is exhausted himself and he was only really in heat for a couple hours. (Okay, probably several hours, but not three days.) He should go downstairs and stand watch until Edge has recovered. Make himself useful.

But when he tries to sit up, wobbling on his shaky limbs, wrung out, Edge stirs beneath him. He tangles his fingers in Sans's t-shirt, keeping him still. Sounding tired and a little lost, he mumbles, "Sans?"

It's pretty clear that Sans isn't the one he actually means.

Sans gives up. Nobody's come in and killed them yet. Might as well keep testing their luck. He lets Edge pull him back down and draw him securely against his side, one arm wrapped protectively around him. Sans leans his head against Edge's scarred ribs and Edge pets him in his sleep, more misdirected tenderness that Sans soaks up with guilty greed.

He misses Papyrus; they've never been apart for this long. He misses his home. He wants to stop tasting dust with every breath he takes and flinching at every loud noise outside. But being like this with Edge, letting Edge hold him... it makes his soul ache less. It's pathetic, but being pathetic has never stopped him before. 

Their brothers aren’t here. Right now the only thing they have is each other.

"It's okay," he says, quiet. "I'm not going anywhere."


End file.
